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Flywheel Lightening


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#16 ACDodd

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Posted 08 March 2019 - 10:31 PM

If you are using it for trackwork you need a steel flywheel.
The all factory flywheels are cast iron and at fine for road use. If you want to rev to 7krpm, you should be fitting a steel flywheel. (Then again why work you be revving to 7krpm in a road engined mini)

Ac

Edited by ACDodd, 10 March 2019 - 08:21 AM.


#17 JonnyAlpha

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Posted 09 March 2019 - 11:38 PM

So for a road car with an MG Metro 12G940 head slightly modded, rebore to 1293, Evo001 Cam, Should I have the stock Cast Iron Flywheel lightened.

#18 nicklouse

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Posted 10 March 2019 - 12:29 AM

So for a road car with an MG Metro 12G940 head slightly modded, rebore to 1293, Evo001 Cam, Should I have the stock Cast Iron Flywheel lightened.

it is up to you. but dont just ask any one to do it.

 

but there are also many other things to consider. first is it verto or not? if verto then are you changing the pressure side? if yes then the assy needs balancing. and then you may as well get the flywheel side faced and lightened and balanced along with the new pressure plate.

 

if pre verto. then again if the back plate and flywheel need a face then a rebalance will be needed so a lightening may as well be done at the same time. remember to include the spring cover.



#19 DeadSquare

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Posted 10 March 2019 - 10:23 AM

So for a road car with an MG Metro 12G940 head slightly modded, rebore to 1293, Evo001 Cam, Should I have the stock Cast Iron Flywheel lightened.

 

No.

 

 

The biggest argument for lightening a flywheel is that for ever after, you drive round with 3 lbs less weight, but that will make a sod all point 02% difference to your acceleration.

 

The math formula for spinning up the flywheel and accelerating the car is the same, and it contains the element Time.   Mass X Meters per Second per Second.

 

Some people, claiming that a lighter flywheel requires less energy to spin it up to a given speed, assume that that energy would be available to accelerate the car, which all things being equal, is correct.

 

However, things are not equal as it takes much more time, and therefore less energy per second, to spin the flywheel up to the given speed with the added load of accelerating the car, than it does to spin up an unloaded flywheel.

 

Put simplistically, to make things equal, the weight of the flywheel would have to be reduced to its square root for the assumed energy to become available, because in the acceleration formula the Time element is squared,



#20 ACDodd

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Posted 10 March 2019 - 11:52 AM

Fact, fitting a lighter cast iron flywheel to a standard engjne, you will feel the benefit. Fitting one to you planned spec is a good way forward.

Ac

#21 DeadSquare

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Posted 10 March 2019 - 02:35 PM

Fact, fitting a lighter cast iron flywheel to a standard engjne, you will feel the benefit. Fitting one to you planned spec is a good way forward.

Ac

 

 I bow to your much greater experience.

 

But as Mandy Rice-Davies said,   ...   "You would say that"   ...   because you lighten them,  Lol.


Edited by DeadSquare, 11 March 2019 - 09:18 AM.


#22 Carlos W

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Posted 10 March 2019 - 02:41 PM

Fact, fitting a lighter cast iron flywheel to a standard engjne, you will feel the benefit. Fitting one to you planned spec is a good way forward.

Ac

 
 I bow to your much greater experience.
 
But as Mandy Rice-Davies said,   ...   "You would say that"   ...   because you make money from lightening them,  Lol.

He's never short of work though. In fact, sometimes he's turning it away.

He provides a lot of knowledge to this forum and to others free of charge and to be quite honest I find your comment rude.

#23 DeadSquare

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Posted 10 March 2019 - 03:04 PM

 

 

Fact, fitting a lighter cast iron flywheel to a standard engjne, you will feel the benefit. Fitting one to you planned spec is a good way forward.

Ac

 
 I bow to your much greater experience.
 
But as Mandy Rice-Davies said,   ...   "You would say that"   ...   because you make money from lightening them,  Lol.

He's never short of work though. In fact, sometimes he's turning it away.

He provides a lot of knowledge to this forum and to others free of charge and to be quite honest I find your comment rude.

 

 

 

I do beg your pardon.  I respect your honesty and I am very sorry that you took it that way.

 

The second line was entirely meant to be tongue-in-cheek.

 

Perhaps I am too old to be alluding to the famous Profumo scandal.



#24 Cooperman

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Posted 10 March 2019 - 04:04 PM

Are the wide starter rings still available? I recall years ago that a machine-shop friend of mine would always fit a wider starter ring when lightening a cast iron flywheel as he claimed it 'held it all together better' at high revs.

 

There is no doubt that the standard Mini flywheel, especially the Verto set-up, is too heavy for any sort of performance use. It definitely helps to improve acceleration, especially when combined with reduction of weight from the car by removing the sound-deadening 'goo' on the floors, fitting poly-carbonate windows and having a lower FDR. It won't improve top speed though.



#25 Carlos W

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Posted 10 March 2019 - 07:17 PM

Are the wide starter rings still available? I recall years ago that a machine-shop friend of mine would always fit a wider starter ring when lightening a cast iron flywheel as he claimed it 'held it all together better' at high revs.
 
There is no doubt that the standard Mini flywheel, especially the Verto set-up, is too heavy for any sort of performance use. It definitely helps to improve acceleration, especially when combined with reduction of weight from the car by removing the sound-deadening 'goo' on the floors, fitting poly-carbonate windows and having a lower FDR. It won't improve top speed though.


And eating less pies

#26 Moke Spider

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Posted 11 March 2019 - 12:16 AM

 

Fact, fitting a lighter cast iron flywheel to a standard engjne, you will feel the benefit. Fitting one to you planned spec is a good way forward.

Ac

 

 I bow to your much greater experience.

 

But as Mandy Rice-Davies said,   ...   "You would say that"   ...   because you make money from lightening them,  Lol.

 

 

You can have a difference of opinion, that's fine, however, there's no need to carry on in this way, as Carlos pointed that's just plain rude and it won't win you any respect around here.

 

AC and I rarely see things the same way on a technical level, but we still respect each other on a personal level and show that common courtesy.

 

AC is running a commercial business and freely gives up his time to share his experience here. While he could take advantage of that to pedal his wares, I'm yet to see that, his posts are always such that you can take his advice and spend your money elsewhere. Few who run commercial enterprises will give much more than the time of day.

 

DS, I actually feel an apology to AC and the forum in general wouldn't go astray here mate.

 

For what it's worth, fitting a lightened flywheel or whole bottom end to any engine, standard or modified usually extends the life of the bottom end, so is quite beneficial in that regard, but for Mr & Mrs Average, it can make them a little more fussy to drive.



#27 Dusky

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Posted 11 March 2019 - 12:56 AM

Out of experience, I fitted a lighter flywheel to the same engine spec. It was amazing.

As a physicist: You(deadsquare)'re using the wrong formula. You're mixing linear acceleration with the rotational acceleration of a flywheel/car wheels. These have nothing to do with each other. You're not even thinking about gearing, as the weight loss sensed by the car will be different in every gear. Back to the drawing table, or the school bench!

Edited by Dusky, 11 March 2019 - 12:57 AM.


#28 grizzler73

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Posted 11 March 2019 - 10:37 AM

Out of experience, I fitted a lighter flywheel to the same engine spec. It was amazing.

As a physicist: You(deadsquare)'re using the wrong formula. You're mixing linear acceleration with the rotational acceleration of a flywheel/car wheels. These have nothing to do with each other. You're not even thinking about gearing, as the weight loss sensed by the car will be different in every gear. Back to the drawing table, or the school bench!

 

Thanks Dusky

I was thinking that it sounded wrong but couldn't put my finger on it, that's the great thing about this forum, full of cleverer people than me!

I mainly looked out the window in physics at school unfortunately...



#29 Cooperman

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Posted 11 March 2019 - 01:13 PM

Play nicely please🤗

#30 Retroman

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Posted 11 March 2019 - 02:19 PM

As a rough guide....

 

Depends where the weight is from relative to the crank centre line, the gearing, the weight removed and the weight of the car

 

The weight from any internal lightening is approx 1:10 in 1st gear

 

So 1kg off engine internals is approx 10 kg off the car as you go through each gear the 1:10 reduces

 

There is a formula in DV's book

 

It has no affect on top speed, but you will get there quicker....

 

Megalite Fw, alloy spacers, 3 straps, En24 lightened bolts, Alloy Back Plate Ti bolts. Whole set up 4.8 kg

 

GwSAh6A.jpg






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